Bobro Low Rider Rear BUIS.
The Bobro Engineering LowRider sights are designed from the start to be an extremely low profile set of BUIS for a specific purpose. Many Short Barreled Rifle owners have run into an issue with figuring out how to mount a set of BUIS on the upper and still fit their needed Lights, Lasers and Optics. The idea was to make it so that the Rear Sight was so low profile that there was almost no possible way it could interfere with optics and the Front Sight could easily be mounted under the front arm of the optic mount. This keeps them out of the way, but can still be used in the even the primary optic has a failure.
Even though these sights were designed to fill a specific need, they can still be used on a full size rifle in traditional BUIS positions as shown below. The LowRider sights still maintain all of the adjustability of a standard set of BUIS such as Windage and Elevation and lock in place when flipped up. Just press the button on the side to release them and they lay flat.